/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.tsfile.read.common.block.column;

import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.read.common.block.TsBlock;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

public class TsBlockSerde {

    /**
     * Deserialize a tsblock.
     *
     * @param byteBuffer serialized tsblock.
     * @return Deserialized tsblock.
     */
    public TsBlock deserialize(ByteBuffer byteBuffer) {

        // Serialized tsblock:
        //    +-------------+---------------+---------+------------+-----------+----------+
        //    | val col cnt | val col types | pos cnt | encodings  | time col  | val col  |
        //    +-------------+---------------+---------+------------+-----------+----------+
        //    | int32       | list[byte]    | int32   | list[byte] |  bytes    | byte     |
        //    +-------------+---------------+---------+------------+-----------+----------+

        // Value column count.
        int valueColumnCount = byteBuffer.getInt();

        // Value column data types.
        List<TSDataType> valueColumnDataTypes = new ArrayList<>(valueColumnCount);
        for (int i = 0; i < valueColumnCount; i++) {
            valueColumnDataTypes.add(TSDataType.deserializeFrom(byteBuffer));
        }

        // Position count.
        int positionCount = byteBuffer.getInt();

        // Column encodings.
        List<ColumnEncoding> columnEncodings = new ArrayList<>(valueColumnCount + 1);
        for (int i = 0; i < valueColumnCount + 1; i++) {
            columnEncodings.add(ColumnEncoding.deserializeFrom(byteBuffer));
        }

        // Time column.
        TimeColumn timeColumn =
                ColumnEncoderFactory.get(columnEncodings.get(0)).readTimeColumn(byteBuffer, positionCount);

        // Value columns
        Column[] valueColumns = new Column[valueColumnCount];
        for (int i = 0; i < valueColumnCount; i++) {
            // Value column.
            valueColumns[i] =
                    ColumnEncoderFactory.get(columnEncodings.get(1 + i))
                            .readColumn(byteBuffer, valueColumnDataTypes.get(i), positionCount);
        }

        return new TsBlock(positionCount, timeColumn, valueColumns);
    }

    /**
     * Serialize a tsblock.
     *
     * @param tsBlock The tsblock to serialize.
     * @return Serialized tsblock.
     */
    public ByteBuffer serialize(TsBlock tsBlock) throws IOException {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        DataOutputStream dataOutputStream = new DataOutputStream(byteArrayOutputStream);

        // Value column count.
        dataOutputStream.writeInt(tsBlock.getValueColumnCount());

        // Value column data types.
        for (int i = 0; i < tsBlock.getValueColumnCount(); i++) {
            tsBlock.getColumn(i).getDataType().serializeTo(dataOutputStream);
        }

        // Position count.
        dataOutputStream.writeInt(tsBlock.getPositionCount());

        // Column encodings.
        tsBlock.getTimeColumn().getEncoding().serializeTo(dataOutputStream);
        for (int i = 0; i < tsBlock.getValueColumnCount(); i++) {
            tsBlock.getColumn(i).getEncoding().serializeTo(dataOutputStream);
        }

        // Time column.
        ColumnEncoder columnEncoder = ColumnEncoderFactory.get(tsBlock.getTimeColumn().getEncoding());
        columnEncoder.writeColumn(dataOutputStream, tsBlock.getTimeColumn());

        for (int i = 0; i < tsBlock.getValueColumnCount(); i++) {
            // Value column.
            columnEncoder = ColumnEncoderFactory.get(tsBlock.getColumn(i).getEncoding());
            columnEncoder.writeColumn(dataOutputStream, tsBlock.getColumn(i));
        }

        return ByteBuffer.wrap(byteArrayOutputStream.toByteArray());
    }
}
